Switching power supply device

ABSTRACT

A switching power supply device includes: a plurality of power supply circuits which include a first power supply circuit and a second power supply circuit and respectively correspond to a plurality of phases of a multiphase AC power supply; a switching circuit; an inrush current prevention (ICP) circuit; and a control circuit. The control circuit causes the switching circuit to switch a phase to be connected to the second power supply circuit to a phase corresponding to the first power supply circuit, and causes the ICP circuit to function so that initial charge of electrolyte capacitors included in the respective power supply circuits is performed. After the initial charge is completed, the control circuit causes the switching circuit to switch the phase to be connected to the second power supply circuit to the phase corresponding to the second power supply circuit, and causes the ICP circuit to turn off.

This application is a U.S. national stage application of the PCTInternational Application No. PCT/JP2017/003278 filed on Jan. 31, 2017,which claims the benefit of foreign priority of Japanese patentapplication No. 2016-052201 filed on Mar. 16, 2016, the contents all ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a switching power supply device.

BACKGROUND ART

Conventionally, a power supply device is known which convertsalternating-current (AC) power from a multiphase AC power supply intodirect-current (DC) power (for example, see Patent Literature 1).

CITATION LIST Patent Literature

PTL 1: Japanese Patent Unexamined Publication No. 2012-10507

SUMMARY OF THE INVENTION

The present disclosure provides a switching power supply device which iscapable of reducing the cost and the size of the device.

A switching power supply device according to one embodiment of thepresent disclosure includes a plurality of power supply circuits, aswitching circuit, an inrush current prevention circuit, and a controlcircuit. The plurality of power supply circuits include a first powersupply circuit and a second power supply circuit, and respectivelycorrespond to a plurality of phases of a multiphase AC power supply. Theswitching circuit switches a phase to be connected to the second powersupply circuit between a phase corresponding to the first power supplycircuit and a phase corresponding to the second power supply circuit.The inrush current prevention circuit is disposed on a negative powerline of the multiphase AC power supply, at a position closer to themultiphase AC power supply than a connection point is. The plurality ofpower supply circuits are connected with each other at the point. Theinrush current prevention circuit prevents inrush current. The controlcircuit controls the switching circuit and the inrush current preventioncircuit. The control circuit causes the switching circuit to switch thephase to be connected to the second power supply circuit to the phasecorresponding to the first power supply circuit, and causes the inrushcurrent prevention circuit to function so that initial charge ofcapacitors respectively included in the plurality of power supplycircuits is performed. Moreover, when the initial charge of thecapacitors is completed, the control circuit causes the switchingcircuit to switch the phase to be connected to the second power supplycircuit to the phase corresponding to the second power supply circuit,and causes the inrush current prevention circuit to turn off.

According to the present disclosure, it is possible to provide aswitching power supply device capable of reducing the cost and the sizeof the device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a circuit diagram illustrating a case where a switching powersupply device according to a first exemplary embodiment of the presentdisclosure is connected to a single-phase AC power supply.

FIG. 2 is a flowchart of an operation example of the switching powersupply device according to the first exemplary embodiment of the presentdisclosure.

FIG. 3 is a circuit diagram illustrating a case where the switchingpower supply device according to the first exemplary embodiment of thepresent disclosure is connected to a two-phase AC power supply.

FIG. 4 is a circuit diagram illustrating a case where the switchingpower supply device according to the first exemplary embodiment of thepresent disclosure is connected to the two-phase AC power supply.

FIG. 5 is a circuit diagram illustrating a configuration example of aswitching power supply device according to a comparative exampledescribed in the first exemplary embodiment of the present disclosure.

FIG. 6 is a circuit diagram illustrating a case where a switching powersupply device according to a second exemplary embodiment of the presentdisclosure is connected to a single-phase AC power supply.

FIG. 7 is a circuit diagram illustrating a case where the switchingpower supply device according to the second exemplary embodiment of thepresent disclosure is connected to a two-phase AC power supply.

FIG. 8 is a circuit diagram illustrating a case where the switchingpower supply device according to the second exemplary embodiment of thepresent disclosure is connected to the two-phase AC power supply.

FIG. 9 is a circuit diagram illustrating a case where the switchingpower supply device according to the second exemplary embodiment of thepresent disclosure is connected to a three-phase AC power supply.

FIG. 10 is a circuit diagram illustrating a case where the switchingpower supply device according to the second exemplary embodiment of thepresent disclosure is connected to the three-phase AC power supply.

FIG. 11 is a circuit diagram illustrating a configuration example of aswitching power supply device according to a comparative exampledescribed in the second exemplary embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Prior to the description of embodiments of the present disclosure,problems in a conventional technology will be briefly described. In acase where an inrush current prevention circuit for protecting thecircuit from inrush current is disposed for each phase in a power supplydevice which can receive AC power from a multiphase AC power supply, thecost and size of the power supply device are increased.

Hereinafter, respective embodiments of the present disclosure will bedescribed in detail with reference to the drawings.

(First Exemplary Embodiment)

First, an example of a configuration of switching power supply device100 according to the present embodiment will be described with referenceto FIG. 1. FIG. 1 is a circuit diagram illustrating a configurationexample of switching power supply device 100. Switching power supplydevice 100 may be used in, for example, a charging device for vehicles(for example, electric vehicles or hybrid vehicles), or in anotherdevice.

Switching power supply device 100 converts AC power from an AC powersupply into DC power, and outputs the DC power to high-voltage battery20. In FIG. 1, single-phase AC power supply 10 a is illustrated as anexample; however, two-phase AC power supply 10 b may be applied (seeFIG. 3 and FIG. 4). High-voltage battery 20 is, for example, a batteryfor driving the motor of a vehicle. An example of high-voltage battery20 is a lithium ion battery.

Switching power supply device 100 includes power supply circuit 1 a,power supply circuit 1 b, switching circuit 7, inrush current preventioncircuit 12, and control circuit 17. Switching power supply device 100includes two power supply circuits 1 a and 1 b in order to correspond tothe two-phase AC power supply.

Each of power supply circuits 1 a and 1 b includes power supply filter2, AC/DC converter 3, and DC/DC converter G.

Power supply filter 2 receives AC power from single-phase AC powersupply 10 a or two-phase AC power supply 10 b. Power supply filter 2prevents noise from entering the power supply line and flowing out ofthe power supply line.

AC/DC converter 3 is disposed in a subsequent stage of power supplyfilter 2. AC/DC converter 3 converts the AC power from power supplyfilter 2 into DC power, and outputs the DC power to DC/DC converter 6.

Moreover, AC/DC converter 3 includes: electrolytic capacitor 4 on whichinitial charge (pre-charge) is performed; and voltmeter 5 which measuresthe voltage of electrolytic capacitor 4. The voltage value measured byvoltmeter 5 is output to control circuit 17.

DC/DC converter 6 is disposed in a subsequent stage of AC/DC converter3. DC/DC converter 6 transforms the DC voltage from AC/DC converter 3 todifferent DC voltage, and outputs the transformed DC voltage tohigh-voltage battery 20.

Switching circuit 7 switches between a first mode in which only powersupply circuit 1 a is driven when the AC power supply is single-phase ACpower supply 10 a and a second mode in which power supply circuit 1 aand power supply circuit 1 b are driven when the AC power supply istwo-phase AC power supply 10 b. In other words, switching circuit 7 iscapable of switching the phase to be connected to the power supplycircuit (for example, 1 b) which does not correspond to a given phase(for example, L1) of the multiphase AC power supply (for example, 10 b),among a plurality of power supply circuits 1 a and 1 b, between thegiven phase of the multiphase AC power supply and the phase (forexample, L2) corresponding to the power supply circuit.

Switching circuit 7 includes switching relay 8, coil 9, and drivecircuit 11. Drive circuit 11 switches between on and off of switchingrelay 8 in response to a control signal from control circuit 17. Thiscontrol signal indicates turning on switching relay 8 or turning offswitching relay 8.

The off-state of switching relay 8 refers to the state, as illustratedin FIG. 1, where switching relay 8 is connected to one of power supplylines L1 branched at branch point n2. In contrast, the on-state ofswitching relay 8 refers to the state, as illustrated in FIG. 4, whereswitching relay 8 is connected to power supply line L2. Note that branchpoint n2 is a point (position) on the positive power supply line L1(first phase).

Inrush current prevention circuit 12 is disposed at a position closer tosingle-phase AC power supply 10 a than meeting point (connection point)n3 is. The negative line of power supply circuit 1 a and the negativeline of power supply circuit 1 b are connected with each other atmeeting point n3. Inrush current prevention circuit 12 limits inrushcurrent. Meeting point n3 is a point (position) on negative power supplyline N.

Inrush current prevention circuit 12 includes: inrush current limitingcircuit 13 including a fuse and an inrush current limiting resistor;inrush prevention relay 14; coil 15; and drive circuit 16. Drive circuit16 switches between on and off of inrush prevention relay 14 in responseto a control signal from control circuit 17. This control signalindicates turning on inrush prevention relay 14 or turning off inrushprevention relay 14. Note that FIG. 1 illustrates, as an example, a casewhere inrush prevention relay 14 is off. FIG. 4 illustrates, as anexample, a case where inrush prevention relay 14 is on.

Control circuit 17 is configured of, for example, a central processingunit (CPU), a read only memory (ROM), and a random-access memory (RAM).

For example, control circuit 17 causes switching circuit 7 to switch thephase to be connected to the power supply circuit (for example, 1 b)which does not correspond to a given phase (for example, L1) to thegiven phase, and causes inrush current prevention circuit 12 to function(turns off inrush prevention relay 14) so that initial charge ofelectrolyte capacitors 4 included respectively in the power supplycircuits (for example, 1 a, 1 b) is performed. When the initial chargeof electrolyte capacitors 4 is completed, control circuit 17 causesswitching circuit 7 to switch the phase to be connected to the powersupply circuit which does not correspond to the given phase to the phase(for example, L2) corresponding to the power supply circuit, and turnsoff inrush current prevention circuit 12 (turns on inrush preventionrelay 14). Note that the details of the control performed by controlcircuit 17 will be described later with reference to FIG. 2.

An example of the configuration of switching power supply device 100 hasbeen described above.

Next, an example of an operation of switching power supply device 100will be described with reference to FIG. 2. FIG. 2 is a flowchart of anoperation example of switching power supply device 100. The operationdescribed below starts, for example, when an AC power supply is poweredon. At this time, both switching relay 8 and inrush prevention relay 14are off.

First, control circuit 17 determines the specification of the connectedAC power supply (step S100). Specifically, control circuit 17 determineswhether the AC power supply is single-phase AC power supply 10 a ortwo-phase AC power supply 10 b.

Next, control circuit 17 performs control according to the determinedspecification of the AC power supply such that charging (initial charge)of electrolyte capacitor 4 of AC/DC converter 3 is performed (stepS101).

Specifically, when the specification of the AC power supply issingle-phase AC power supply 10 a, control circuit 17 performs controlsuch that initial charge of electrolyte capacitor 4 of AC/DC converter 3of power supply circuit 1 a is performed. At this time, switching relay8 and inrush prevention relay 14 are off as illustrated in FIG. 1.

Since inrush prevention relay 14 is off at this time, power suppliedfrom single-phase AC power supply 10 a is supplied to power supplycircuit 1 a via power supply line L1, and is also supplied to the inrushcurrent limiting resistor of inrush current limiting circuit 13. Thisallows charging (initial charge) of electrolyte capacitor 4 of powersupply circuit 1 a to be performed while preventing inrush current fromflowing to power supply circuit 1 a.

In contrast, when the specification of the AC power supply is two-phaseAC power supply 10 b, control circuit 17 performs control such thatinitial charge of electrolyte capacitor 4 of AC/DC converter 3 in eachof power supply circuits 1 a and 1 b is performed. At this time,switching relay 8 and inrush prevention relay 14 are off as illustratedin FIG. 3. Note that n1 in FIG. 3 refers to a neutral point.

Since switching relay 8 and inrush prevention relay 14 are off at thistime, power supplied from two-phase AC power supply 10 b is supplied topower supply circuit 1 a and power supply circuit 1 b via power supplyline L1, and is also supplied to the inrush current limiting resistor ofinrush current limiting circuit 13. In other words, the circuitconfiguration is such that power supply circuit 1 a, power supplycircuit 1 b, and inrush current limiting circuit 13 are connectedbetween neutral point n1 and the first phase (L1) of two-phase AC powersupply 10 b. The inrush current limiting resistor of inrush currentlimiting circuit 13 allows charging (initial charge) of electrolytecapacitor 4 of each of power supply circuits 1 a and 1 b to be performedwhile preventing inrush current from flowing to power supply circuits 1a and 1 b.

After the above control, control circuit 17 receives the voltage valuesof electrolytic capacitors 4 measured by voltmeters 5, respectively.

Next, control circuit 17 compares the voltage value received from eachof voltmeters 5 with a predetermined threshold value to determinewhether the initial charge of electrolytic capacitors 4 is completed(step S102).

For example, when one of more of the voltage values from voltmeters 5have not reached the threshold value, control circuit 17 determines thatthe initial charge is not completed (step S102: NO). In this case, theflow returns to step S102.

In contrast, for example, when the voltage values from all of voltmeters5 have reached the threshold value, control circuit 17 determines thatthe initial charge is completed (step S102: YES). In this case, the flowproceeds to step S103.

Here, when the specification of the AC power supply determined in stepS100 is single-phase AC power supply 10 a (step S103: single phase),control circuit 17 turns on inrush prevention relay 14 (step S105). Atthis time, switching relay 8 is controlled to remain off. Then, onlypower supply circuit 1 a is driven so that high-voltage battery 20 ischarged (first mode).

In contrast, when the specification of the AC power supply determined instep S100 is multiphase (for example, two-phase AC power supply 10 b)(step S103: multiphase), control circuit 17 turns on switching relay 8as illustrated in FIG. 4 (step S104). Accordingly, the circuitconfiguration is such that power supply circuit 1 a and power supplycircuit 1 b correspond to respective phases. In other words, the circuitconfiguration is such that power supply circuit 1 a is connected toneutral point n1 and the first phase (L1) of two-phase AC power supply10 b therebetween, and power supply circuit 1 b is connected to neutralpoint n1 and the second phase (L2) of two-phase AC power supply 10 btherebetween.

Then, control circuit 17 turns on inrush prevention relay 14 (stepS105). Accordingly, both power supply circuits 1 a and 1 b are driven sothat high-voltage battery 20 is charged (second mode).

An example of the operation of switching power supply device 100 hasbeen described above.

FIG. 5 illustrates a configuration example of switching power supplydevice 101 as an example compared to the first exemplary embodiment.Note that in FIG. 5, the structural elements which are the same as inFIG. 1, FIG. 3, and FIG. 4 are illustrated with the same referencenumerals, and description of such structural elements is omitted.

As illustrated in FIG. 5, in switching power supply device 101, inrushcurrent prevention circuits 12 are disposed both in power supply circuit1 a and power supply circuit 1 b. In such a configuration, a pluralityof inrush current prevention circuits 12 are required, which causesproblems of increased cost and size of switching power supply device101.

In contrast, in switching power supply device 100 according to thepresent embodiment, one inrush current prevention circuit 12 is disposeddownstream of meeting point n3. In both of the cases where the AC powersupply is single-phase AC power supply 10 a and where the AC powersupply is two-phase AC power supply 10 b, inrush current preventioncircuit 12 is used. Accordingly, it is possible to reduce the cost andsize of switching power supply device 100.

(Second Exemplary Embodiment)

Next, an example of a configuration of switching power supply device 200according to the present embodiment will be described with reference toFIG. 6. FIG. 6 is a circuit diagram illustrating a configuration exampleof switching power supply device 200. Switching power supply device 200includes three power supply circuits (1 a to 1 c) to correspond to athree-phase AC power supply. Note that in FIG. 6, the structuralelements which are the same as in FIG. 1 are illustrated with the samereference numerals, and description of such structural elements isomitted.

Switching power supply device 200 may be used in, for example, acharging device for vehicles (for example, electric vehicles or hybridvehicles), or in another device.

Switching power supply device 200 is different from switching powersupply device 100 illustrated in FIG. 1 in that power supply circuit 1 cand switching circuit 7 a are added. Power supply circuit 1 c has thesame configuration as those of power supply circuits 1 a and 1 b.Moreover, switching circuit 7 a has the same configuration as that ofswitching circuit 7. On and off states of switching relay 8 arecontrolled by control circuit 17.

In a state where switching relay 8 of switching circuit 7 a is off,switching relay 8 is connected to one of power supply lines L1 branchedat branch point n2. In contrast, in a state where switching relay 8 ofswitching circuit 7 a is on, switching relay 8 is connected to powersupply line L3 as illustrated in FIG. 10.

Moreover, FIG. 6 illustrates, as an example, the case where switchingpower supply device 200 is connected to single-phase AC power supply 10a. However, switching power supply device 200 may be connected totwo-phase AC power supply 10 b (see FIG. 7 and FIG. 8) or to three-phaseAC power supply 10 c (see FIG. 9 and FIG. 10).

Inrush current prevention circuit 12 is disposed at a position closer tothe AC power supply than meeting point (connection point) n3 is. Thenegative line of power supply circuit 1 a, the negative line of powersupply circuit 1 b, and the negative line of power supply circuit 1 care connected with each other at meeting point n3. Inrush currentprevention circuit 12 limits inrush current.

Note that in FIG. 6, the negative lines of power supply circuits 1 a to1 c are connected at one meeting point (connection point) n3. However,for example, a first connection point at which the negative line ofpower supply circuit 1 a is connected with the negative line of powersupply circuit 1 b may be different from a second connection point atwhich the negative line of power supply circuit 1 b is connected withthe negative line of power supply circuit 1 c. In this case, inrushcurrent prevention circuit 12 is disposed at a position closer to the ACpower supply than the first connection point and the second connectionpoint are.

In the present embodiment, switching circuits 7 and 7 a switch betweenthe first mode and the second mode described in the first exemplaryembodiment, and the third mode where power supply circuits 1 a, 1 b, and1 c are driven when the AC power supply is three-phase AC power supply10 c.

An example of the configuration of switching power supply device 200 hasbeen described above.

Next, an example of an operation of switching power supply device 200according to the present embodiment will be described with reference toFIG. 2. The operation described below starts, for example, when the ACpower supply is powered on. At this time, switching relay 8 of switchingcircuit 7, switching relay 8 of switching circuit 7 a, and inrushprevention relay 14 are off.

First, control circuit 17 determines the specification of the connectedAC power supply (step S100). Specifically, control circuit 17 determineswhether the AC power supply is single-phase AC power supply 10 a,two-phase AC power supply 10 b, or three-phase AC power supply 10 c.

Next, control circuit 17 performs control according to the determinedspecification of the AC power supply such that charging (initial charge)of electrolyte capacitor(s) 4 of AC/DC converter(s) 3 is performed (stepS101).

Specifically, when the specification of the AC power supply issingle-phase AC power supply 10 a, control circuit 17 performs controlsuch that initial charge of electrolyte capacitor 4 of AC/DC converter 3of power supply circuit 1 a is performed. At this time, switching relay8 of switching circuit 7, switching relay 8 of switching circuit 7 a,and inrush prevention relay 14 are off as illustrated in FIG. 6.

Since inrush prevention relay 14 is off at this time, power suppliedfrom single-phase AC power supply 10 a is supplied to power supplycircuit 1 a via power supply line L1, and is also supplied to an inrushcurrent limiting resistor of inrush current limiting circuit 13. Thisallows charging (initial charge) of electrolyte capacitor 4 of powersupply circuit 1 a to be performed while preventing inrush current fromflowing to power supply circuit 1 a.

Moreover, when the specification of the AC power supply is two-phase ACpower supply 10 b, control circuit 17 performs control such that initialcharge of electrolyte capacitor 4 of AC/DC converter 3 in each of powersupply circuit 1 a and power supply circuit 1 b is performed. At thistime, switching relay 8 of switching circuit 7, switching relay 8 ofswitching circuit 7 a, and inrush prevention relay 14 are off asillustrated in FIG. 7.

Since switching relay 8 of switching circuit 7 and inrush preventionrelay 14 are off at this time, power supplied from two-phase AC powersupply 10 b is supplied to power supply circuit 1 a and power supplycircuit 1 b via power supply line L1, and is also supplied to the inrushcurrent limiting resistor of inrush current limiting circuit 13. Thisallows charging (initial charge) of electrolyte capacitor 4 of each ofpower supply circuit 1 a and power supply circuit 1 b to be performedwhile preventing inrush current from flowing to power supply circuit 1 aand power supply circuit 1 b.

Moreover, when the specification of the AC power supply is three-phaseAC power supply 10 c, control circuit 17 performs control such thatinitial charge of electrolyte capacitor 4 of AC/DC converter 3 in eachof power supply circuit 1 a, power supply circuit 1 b, and power supplycircuit 1 c is performed. At this time, switching relay 8 of switchingcircuit 7, switching relay 8 of switching circuit 7 a, and inrushprevention relay 14 are off as illustrated in FIG. 9.

Since switching relay 8 of switching circuit 7, switching relay 8 ofswitching circuit 7 a, and inrush prevention relay 14 are off at thistime, power supplied from three-phase AC power supply 10 c is suppliedto power supply circuit 1 a, power supply circuit 1 b, and power supplycircuit 1 c via power supply line L1, and is also supplied to the inrushcurrent limiting resistor of inrush current limiting circuit 13. Inother words, the circuit configuration is such that power supply circuit1 a, power supply circuit 1 b, power supply circuit 1 c and inrushcurrent limiting circuit 13 are connected to neutral point n1 and thefirst phase (L1) of three-phase AC power supply 10 c therebetween.Accordingly, the inrush current limiting resistor of inrush currentlimiting circuit 13 allows charging (initial charge) of electrolytecapacitor 4 of each of power supply circuit 1 a, power supply circuit 1b, and power supply circuit 1 c to be performed, while preventing inrushcurrent from flowing to power supply circuit 1 a, power supply circuit 1b, and power supply circuit 1 c.

After the above control, control circuit 17 receives the voltage valueof each of electrolytic capacitor 4 measured by respective one ofvoltmeters 5.

The operation of step S102 is similar to that in the first exemplaryembodiment above, and thus, description of the operation of step S102 isomitted here.

When the specification of the AC power supply determined in step S100 issingle-phase AC power supply 10 a (step S103: single phase), controlcircuit 17 turns on inrush prevention relay 14 (step S105). At thistime, both switching relay 8 of switching circuit 7 and switching relay8 of switching circuit 7 a are controlled to remain off. Then, onlypower supply circuit 1 a is driven so that high-voltage battery 20 ischarged (first mode).

When the specification of the AC power supply determined in step S100 istwo-phase AC power supply 10 b (step S103: multiphase), control circuit17 turns on switching relay 8 of switching circuit 7 (step S104) andturns on inrush prevention relay 14 (step S105), as illustrated in FIG.8. As illustrated in FIG. 8, switching relay 8 of switching circuit 7 ais controlled to remain off. Accordingly, both power supply circuits 1 aand 1 b are driven so that high-voltage battery 20 is charged (secondmode).

When the specification of the AC power supply determined in step S100 isthree-phase AC power supply 10 c (step S103: multiphase), controlcircuit 17 turns on both switching relay 8 of switching circuit 7 andswitching relay 8 of switching circuit 7 a, as illustrated in FIG. 10(step S104). Accordingly, the circuit configuration is such that powersupply circuit 1 a, power supply circuit 1 b, and power supply circuit 1c correspond to respective phases. In other words, the circuitconfiguration is such that power supply circuit 1 a is connected toneutral point n1 and the first phase (L1) of three-phase AC power supply10 c therebetween, power supply circuit 1 b is connected to neutralpoint n1 and the second phase (L2) of three-phase AC power supply 10 ctherebetween, and power supply circuit 1 c is connected to neutral pointn1 and the third phase (L3) of three-phase AC power supply 10 ctherebetween.

Then, control circuit 17 turns on inrush prevention relay 14 (stepS105). Accordingly, all of power supply circuits 1 a, 1 b, and 1 c aredriven so that high-voltage battery 20 is charged (third mode).

An example of the operation of switching power supply device 200 hasbeen described above.

FIG. 11 illustrates a configuration example of switching power supplydevice 201 as an example compared to the second exemplary embodiment.Note that in FIG. 11, the structural elements which are the same as inFIG. 6 to FIG. 10 are illustrated with the same reference numerals, anddescription of such structural elements is omitted.

As illustrated in FIG. 11, in switching power supply device 201, inrushcurrent prevention circuits 12 are disposed in power supply circuit 1 a,power supply circuit 1 b, and power supply circuit 1 c, respectively. Insuch a configuration, a plurality of inrush current prevention circuits12 are required, which causes problems of increased cost and size ofswitching power supply device 201.

In contrast, in switching power supply device 200 according to thepresent embodiment, one inrush current prevention circuit 12 is disposeddownstream of meeting point n3. In all of the cases where the AC powersupply is single-phase AC power supply 10 a, where the AC power supplyis two-phase AC power supply 10 b, and where the AC power supply isthree-phase AC power supply 10 c, inrush current prevention circuit 12is used. Accordingly, it is possible to reduce the cost and size ofswitching power supply device 200.

Although embodiments of the present disclosure have been describedabove, the present disclosure is not limited to those embodiments.Various modifications are possible within the scope of the essence ofthe present disclosure.

For example, in the above embodiments, the example has been describedwhere power supply circuit 1 a, power supply circuit 1 b, and powersupply circuit 1 c are connected to L1 (first phase) when initial chargeof the capacitors is performed. However, the present disclosure is notlimited to such an example. It may be that power supply circuit 1 a,power supply circuit 1 b, and power supply circuit 1 c are connected toL2 (second phase) or L3 (third phase) when initial charge of thecapacitors is performed. In other words, when initial charge of thecapacitors is performed, it is only required that a plurality of powersupply circuits (1 a to 1 c) are connected between a given phase andneutral point n1.

INDUSTRIAL APPLICABILITY

The present disclosure can be applied to a power supply device whichconverts AC power from an AC power supply into DC power.

REFERENCE MARKS IN THE DRAWINGS

1 a, 1 b, 1 c power supply circuit

2 power supply filter

3 AC/DC converter

4 electrolyte capacitor

5 voltmeter

6 DC/DC converter

7, 7 a switching circuit

8 switching relay

9, 15 coil

10 a single-phase AC power supply

10 b two-phase AC power supply

10 c three-phase AC power supply

11, 16 drive circuit

12 inrush current prevention circuit

13 inrush current limiting circuit

14 inrush prevention relay

17 control circuit

20 high-voltage battery

100, 101, 200, 201 switching power supply device

The invention claimed is:
 1. A switching power supply device comprising:a plurality of power supply circuits including a first power supplycircuit and a second power supply circuit, the plurality of power supplycircuits respectively corresponding to a plurality of phases of amultiphase alternating-current (AC) power supply, the plurality of powersupply circuits being connected with each other at a connection point,and the plurality of power supply circuits including capacitors,respectively; a switching circuit, which, in operation, switches a phaseof the plurality of phases to be connected to the second power supplycircuit between a phase corresponding to the first power supply circuitand a phase corresponding to the second power supply circuit; an inrushcurrent prevention circuit, which, in operation, prevents inrush currentand is disposed on a negative power supply line of the multiphase ACpower supply, at a position that is closer to the multiphase AC powersupply than the connection point; and a control circuit, which, inoperation, controls the switching circuit and the inrush currentprevention circuit, wherein the control circuit, in operation, causesthe switching circuit to switch the phase of the plurality of phases tobe connected to the second power supply circuit to the phasecorresponding to the first power supply circuit, and causes the inrushcurrent prevention circuit to function so that initial charge of thecapacitors is performed, and when the initial charge of the capacitorsis completed, the control circuit causes the switching circuit to switchthe phase of the plurality of phases to be connected to the second powersupply circuit to the phase corresponding to the second power supplycircuit, and causes the inrush current prevention circuit to turn off.2. The switching power supply device according to claim 1, wherein eachof the plurality of power supply circuits includes an AC/DC converter,which, in operation, converts AC power into direct-current (DC) power,and a DC/DC converter, which, in operation, transforms DC voltage outputfrom the AC/DC converter, the AC/DC converter includes one of thecapacitors of the plurality of power supply circuits, and a voltmeter,which, in operation, measures a voltage of the one of the capacitors ofthe plurality of power supply circuits, and the control circuit, inoperation, determines, based on a voltage value from the voltmeter,whether or not the initial charge of the one of the capacitors of theplurality of power supply circuits is completed.
 3. The switching powersupply device according to claim 2, wherein the inrush currentprevention circuit includes an inrush current limiting resistor, thefirst power supply circuit corresponds to a first phase of themultiphase AC power supply, the second power supply circuit correspondsto a second phase of the multiphase AC power supply, when a single-phaseAC power supply is applied, the control circuit controls the switchingcircuit and the inrush current prevention circuit when the initialcharge is performed, such that power supplied from the single-phase ACpower supply is supplied to the first power supply circuit via the firstphase and is also supplied to the inrush current limiting resistor, andthe control circuit controls the switching circuit and the inrushcurrent prevention circuit after the initial charge is completed, suchthat power supplied from the single-phase AC power supply is supplied tothe first power supply circuit via the first phase and is not suppliedto the inrush current limiting resistor, and when a two-phase AC powersupply is applied, the control circuit controls the switching circuitand the inrush current prevention circuit when the initial charge isperformed, such that power supplied from the two-phase AC power supplyis supplied to the first power supply circuit and the second powersupply circuit via the first phase and is also supplied to the inrushcurrent limiting resistor, and the control circuit controls theswitching circuit and the inrush current prevention circuit after theinitial charge is completed, such that power supplied from the two-phaseAC power supply is supplied to the first power supply circuit via thefirst phase and to the second power supply circuit via the second phase,and is not supplied to the inrush current limiting resistor.
 4. Theswitching power supply device according to claim 2, wherein the inrushcurrent prevention circuit includes an inrush current limiting resistor,the plurality of power supply circuits further include a third powersupply circuit, the first power supply circuit corresponds to a firstphase of the multiphase AC power supply, the second power supply circuitcorresponds to a second phase of the multiphase AC power supply, thethird power supply circuit corresponds to a third phase of themultiphase AC power supply, when a single-phase AC power supply isapplied, the control circuit controls the switching circuit and theinrush current prevention circuit when the initial charge is performed,such that power supplied from the single-phase AC power supply issupplied to the first power supply circuit via the first phase and isalso supplied to the inrush current limiting resistor, and the controlcircuit controls the switching circuit and the inrush current preventioncircuit after the initial charge is completed, such that power suppliedfrom the single-phase AC power supply is supplied to the first powersupply circuit via the first phase and is not supplied to the inrushcurrent limiting resistor, and when a two-phase AC power supply isapplied, the control circuit controls the switching circuit and theinrush current prevention circuit when the initial charge is performed,such that power supplied from the two-phase AC power supply is suppliedto the first power supply circuit and the second power supply circuitvia the first phase and is also supplied to the inrush current limitingresistor, and the control circuit controls the switching circuit and theinrush current prevention circuit after the initial charge is completed,such that power supplied from the two-phase AC power supply is suppliedto the first power supply circuit via the first phase and to the secondpower supply circuit via the second phase and is not supplied to theinrush current limiting resistor, and when a three-phase AC power supplyis applied, the control circuit controls the switching circuit and theinrush current prevention circuit when the initial charge is performed,such that power supplied from the three-phase AC power supply issupplied to the first power supply circuit, the second power supplycircuit, and the third power supply circuit via the first phase and isalso supplied to the inrush current limiting resistor, and the controlcircuit controls the switching circuit and the inrush current preventioncircuit after the initial charge is completed, such that power suppliedfrom the three-phase AC power supply is supplied to the first powersupply circuit via the first phase, to the second power supply circuitvia the second phase, and to the third power supply circuit via thethird phase and is not supplied to the inrush current limiting resistor.